Prosthesis construction



June 2, 1953 w. WISBRUN PROSTHESIS CONSTRUCTION Filed July 28, 1950 INVENTOR. \X/ALTEP \X/DDPUN BY 4 T TORNEYS Patented June 2, 1953 UNITED STATES PATENT OFFICE PROSTHESIS CONSTRUCTION Walter Wisb'ru'n, Cleveland Heights, Ohio Application J uly28, 1950, Serial N 0. 176,459

Foot and leg prosthesis construction as commonly, known is inadequate. First, it'does not take account of or accommodate to the peculiar rotating or oscillating motion which the leg performs in locomotion. Accordingly, friction of the stump in the socket is prone to cause discomfort. Second, it lacks capability to provide the throw or'centrifugalpower which is concerned in the effortless automatism and the gracefuhiess of thehuman gait. These defects have arisen from will appear from the following description.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

In said annexed drawings:

Fig. l is a plan view of a prosthesis in accordance with the present invention;

Fig. 2 is a vertical section, on slightly larger scale, taken on a plane substantially indicated by line VIII, Fig. 1;

Fig. 3 is a transverse section taken substantially on line IX, Fig. 2;

1 Fig. 4 is a transverse section taken substantially on line X, Fig. 1; and

Figs. 5, 6 and 7 are views generally analogous j-to Figs. 1, 2 and 4, showing a, slight modification.

For an understanding of the invention it is necessary to first briefly refer. to some peculiarities of the anatomy of the foot. The peculiar components of the normal foot, which are essential .for the effortless and graceful character of the human gait, involve: First, upward and downvward rotation of the first metatarsal bone about the sagital axis of the sub-talar joint; second, rotation about the vertical axis of this articulation, creating centrifugal power; and third. ar-

rest of the centrifugal motion converting it into 11 Claims. (Cl. 3-6) propelling motion. These factors are taken account of in prosthesis construction, as illustrated, referring first to Figs. 1 1. Here, a leg Dost L from a socket of any desired form is articulated to a foot plate made up of a steel plate 3 having some resiliency, and with cushioning rubber -4 forming a generally foot-like contour. Between the leg post and the foot plate are two joints. Articulating with the foot plate is an intermediate post portion 5 which has a forward extension 0 terminating in a cylindrical head 1 which is mounted in the assemblable bearingyll suitably secured to the plate 3. The composite bearing allows assembly such that the ends of the cylindrical head! are, overhungbythe bearing structure and the joint is held against separation, while allowing a limited rocking motion of the foot plate on the member 5, within the limits of the cut-away margins of the plate 3 and bearing. It is to be especially noticed that a peculiarity of this joint is that it is diagonally oriented with respect to the toe-heel axis. That is, the outer end of the cylindrical head 1 is further forward than the medial or inner end. This peculiar orientation of the joint gives a result that when the foot plate is tipped down at the toe-end, it is also moved inwardly within the limits of the movement, and when the foot plate is-reversely rocked, the toe-end is thrown upwardly and outwardly. The importance of this will appear from the description further on. A spring I0 in a socket in the member 5 and bearing against the plate 3 thereunder, normally tends to urge the foot plate in the the toe-end in its elevated phase. V.

. Between the leg post L and the member 5 is a joint for limited rotation on a vertical axis. This may be formed for instance on the order of an assemblable joint with an extension head I2 integral with the member and of T-form. The lower end of the leg post L is closed except for a transverse slot I 4 which is of dimensions to allow the T-head [2 to slide through when the foot plate is turned transversely. Thus, assembly of the foot plate with its attached post-member 5 can have the T-head inserted through thereceiving slot I4 when in transverse position, and on then turning the foot plate back to normal toe-forward position the T-head l2 rides on the annular shoulder [5 of the lower end of the leg post L, and disengagement of this joint would be possible only if the foot were to be turned back transversely such as to register the T.-hea d 1-2 with the entry slot. Such disassembly is prevented by a stop-screw l6 which may be set into position with stem and the intermediate member, a limit-screw set through a horizontal slot above said shoulder and the leg stem and into the T-head to limit the extent of rotary movement, a spring between the base of'said intermediate member and the subjacent cover plate, an arm extending forwardly from said leg stem over the foot-plate, an

anti-friction roller in the free end of said arm, and a spring with one end secured to the outer edge of the foot-plate and extending inunder said roller.

3. In prosthesis construction, a leg stem, a footplate, an intermediate member between said leg stem and said foot-plate having a forwardly and downwardly extending portion terminating in a diagonally oriented bearing member of generally cylindrical form, a receiving bearing overhanging the ends of the latter in the foot-plate and permitting limited rocking movement, a general cover plate on the foot-plate to which said receiving bearing is secured, a T-head extension at the top of said intermediate member, a shoulder in the lower end of the leg stem with partial interruption by a slot to receive said T-head when the foot-plate is turned transversely, thereby forming a rotary joint between the leg stem and the intermediate member, a limit-screw set through a horizontal slot above said shoulder and the leg stem and into the T-head to limit the extent of rotary movement, a spring between the base of said intermediate member and the subjacent cover plate, an arm extending forwardly of the leg stem axis allowing end movement with relation to the foot-plate and capable of transmitting pressure to the foot-plate in front of the rocker-joint when the leg stem inclines forward in locomotion, and a spring with one end secured to the outer edge of the foot-plate and extending in under said forward arm.

4. In prosthesis construction, a leg stem, a footplate, an intermediate member between said leg stem and said foot-plate having a forwardly and downwardly extending portion terminating in a diagonally oriented bearing member of generally cylindrical form, a receiving bearing overhanging the ends of the latter in the foot-plate and permitting limited rocking movement, a general cover plate on the foot-plate to which said receiving bearing is secured, a T-head extension at the top of said intermediate member, a shoulder in the lower end of the leg stem with partial interruption by a slot to receive said T-head when the foot-plate is turned transversely, thereby forming a rotary joint between the leg stem and the intermediate member, a limit-screw set through a horizontal slot above said shoulder and the leg stem and into the T-head to limit the extent of rotary movement, a spring between the base of said intermediate member and the subjacent cover plate, an arm secured to the leg stem and extending forwardly over the footplate, and a spring with one end secured to the outer edge of the foot-plate and extending in under said forwardly extending arm.

5. In prosthesis construction, a leg stem, a footplate, an intermediate member between said leg stem and said foot-plate having a forwardly and downwardly extending portion terminating in a diagonally oriented bearing member of generally cylindrical form, a receiving bearing overhanging the ends of the latter in the foot-plate and permitting limited rocking movement, a general cover plate on the foot-plate to which said receiving bearing is secured, a limited motion rotary joint between said leg stem and said intermediate member, an arm extending forwardly of the leg stem axis allowing independent movement with relation to the foot-plate and capable of transmitting pressure to the foot plate in front of the rocker joint when the leg stem inclines forward in locomotion, and a spring withone end secured to the outer edge of the foot plate and extending under-said forwardarm. w

6. In prosthesis construction,aleg'stem, a footplate, an intermediate member between said leg stem and said foot-plate having a forwardly and downwardly extending portion .terminating in a diagonally oriented bearing member of generally cylindrical form, a receiving bearing overhanging the ends of the latter in the foot-plate and permitting limited rocking movement, a general cover plate on the foot-plate to which said receiving bearing is secured, a limited motion rotary joint between said leg stem and said intermediate member, and an arm extending forwardly of the leg stem axis fo independent movement with relation to the foot-plate and transmission of pressure to the foot-plate in front of the rocker-joint when the leg stem inclines forward in locomotion.

7. In prosthesis construction, a leg stem, a. foot-plate, an intermediate member between said leg stem and said foot-plate having a forwardly and downwardly extending portion terminating in a diagonally oriented bearing member of generaly cylindrical form, a receiving bearing overhanging the ends of the latter in the foot-plate and permitting limited rocking movement, a general cover plate on the foot-plate to which said receiving bearing is secured, a longitudinal slit in the forward end of said cover plate, and a rotary joint between said leg stem and said intermediate member including a T-head extension on said intermediate member and a shoulder in the lower end of the leg stem with partial interruption by a slot to receive said T-head when the foot-plate is turned transversely.

8. In prosthesis construction, a leg stem, at foot-plate, an intermediate member between said leg stem and said foot-plate, a rotary joint between the leg stern and intermediate member including a T-shaped head on the intermediate member and a shoulder in the adjacent end of the leg stem with partial interruption by a transverse slot to receive said T-shaped head when the foot-plate is turned transversely, and a limit screw to prevent disengagement and allow limited rotary movement.

9. In prosthesis construction, a leg stem, a foot-plate articulated to said leg stem by means including a rocker-joint, an arm extending forwardly of the leg stem axis allowing independent lateral movement with relation to the foot-plate and capable of transmitting pressure to the footplate in front of the rocker-joint when the leg stem inclines forward in locomotion, and a spring with one end secured to the outer edge of the foot-plate and extending transversely under the end of said forward arm adjacent the foot-plate.

10. In prosthesis construction, a leg stem, a foot-plate, articulating means therebetween permitting relative movement of the forward end of the foot-plate upwardly and outwardly, and downwardly and inwardly, an arm extending for wardly of the leg stem axis allowing independent lateral movement with relation to the foot plate, and transverse spring means pressed by said arm in inward position and urging said arm out wardly on release.

' Number 7 11. In p'r'osthetic construction; a, leg stem, a feet member ineluding a r'silieht steel plate having a longitudinal slit in its forward end separating spring sections unconnected other than 110 the said plate, and joint-means between said foot member and said leg stem.

WAL'I'ER WISBRUN;

References Cited in the file 0f fihi patent UNITED STATES PATENTS Name fifit 2,181,631 Thdifiiisfih Nev. 21, 1939 OTHER REFERENCES Terminal Researeh Reperts 1 on Artificial Limbs, by Gommittee on Artificial Limbs of the National Research; Council. Received in Div. 55 Neqember 13, @947, page 39 Fig. 42. A copy is 10 in Div"; 55 at the Patent Omee; 

